Visible-light-driven activation of persulfate over cyano and hydroxyl group co-modified mesoporous g-C3N4 for boosting bisphenol A degradation

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Vol. 7; no. 10; pp. 5552 - 5560
• Main Authors: Zhang, Sai, Song, Shuang, Gu, Pengcheng, Ma, Ran, Wei, Dongli, Zhao, Guixia, Wen, Tao, Riffat Jehan, Hu, Baowei, Wang, Xiangke
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 2019
• Subjects: Activation; Aging; Bisphenol A; Carbon nitride; Catalysis; catalysts; Catalytic activity; Charge transfer; Current carriers; Cyano groups; Degradation; Electromagnetic absorption; energy; Energy levels; engineering; free radicals; Hydroxyl groups; light; Light levels; moieties; oxidants; Oxidation; Oxidizing agents; porous media; Pretreatment; Quantum efficiency; Sulfates; Water pollution
• ISSN: 2050-7488; 2050-7496; 2050-7496
• DOI: 10.1039/c9ta00339h

In this work, structure-deficient mesoporous g-C3N4 (DMCN) was fabricated via a facile hard template approach with water-bath aging pretreatment. The in situ introduced cyano groups (–C≡N) and hydroxyl groups (–OH) effectively modulated the energy levels, improved visible light absorption, and meanwhile served as strong electron-withdrawing groups, promoting the efficient separation and transfer of photogenerated charge carriers. With the addition of persulfate (PS) as an oxidant, DMCN exhibited superior catalytic activity and stability for bisphenol A (BPA) degradation. 100% BPA could be degraded for optimal DMCN-3.5 with 0.5 g L−1 catalyst and 1.0 g L−1 PS under visible light (420 nm ≤ λ ≤ 780 nm) within 15 min, whose reaction rate (0.317 min−1) was ∼39.6 times higher than that of bulk g-C3N4 (0.008 min−1). Based on EPR and quenching tests, h+ and SO4·− radicals were determined as major oxidizing species in the DMCN/PS/Vis system. The enhanced catalytic performance was mainly attributed to PS serving as the electron acceptor and transfer of photogenerated e− to PS via –C≡N and C–OH groups, resulting in the efficient activation of PS for SO4·− and a high light quantum efficiency. This work gives novel insights into in situ defect engineering for g-C3N4 and offers a new chance for visible-light-induced sulfate radical-based Fenton-like system to govern contaminated water.